Positioning indicator for engine pistons



Oct. 9, 1945. F; H. NDRUS v 2,386,179

POSITIONING INDICATOR' FOR ENGINE PISTONS Filed March 10, 1943 Patented Oct. 9, 1945 POSiTIONiNG INgICATOR FOR- My invention relates toan; indicator for deter:- mining the positions of the pistons in. engine cylinders and particularly to denote when .apiston reached the end of its compression. stroke, especially for the purpose of determining spark plug timing relative to compression by the piston, and? an object of my invention, among others, is to produce an indicator for this purpose that omcs TONS

F'oscocI-f. Andrus, Windsor; Conn. 1 Application March 10, 1943,.s r a1'N i 478,691

shah be simple in construction and particularly etfioient in the results obtained by it'suse.

One form of an indicator embodying my inventi'on: and: in the construction and use of which the oin'ects herein set out; as well as others, may be attained is illustrated the: accompanying drawing, inwhich- H Figure i is a-view section through the uppe portion of the cylinder of an engine illustrating the manner of application thereto and the manner of use of my improved indicator'to denote the position of the cylinder at the end-'of'it's com-- pression stroke. 1

Figure 2 isa View in central lengthwise section through the-indicator; i e 7 Figure 3 is a view of one end of the indicator broken off from the main part to illustrate the relative arrangement offthe indicator rod and its supporting spring. l a

Figure 4 is a view looking at the indicati'n "end of the instrument as denoted by the broken line E--4 of Fig. 2.

Figure 5 is-a View in section on a plane denoted by the broken line 5 -5 of Fig. 2-.

In the accompanying drawing the numeral 5 after explained... An indicator case is rotatably adjustably secured. to the outer end of the adjusting head it, this: case comprising a flange l8 rotatablyattached. to the: head it as by means of screws. lit with. their ends entered into an annular groove 21): in the head l.6.. A barrel. 2 incomprises a part of the indicatoricase said barrel ex.- tending; diametrically across the cente'rof the case at the end. thereof. This barrel contains a sight glass 22' bearing graduations for a purpose to be presently disclosed. The barrel is closed at one end by a screw plug. 2's and. atits opposite end by a nipple 2'4. i u

An indicatorrod 25' extends through. the tubular body; said. rod: being. secured in and extending through a ball. bearing. 25 in a ball cas 21; in the denotes a supporting plug that is in the-form of a tubular-part; this plug having a threaded end I for attachment of'theinstrument within the spark plug opening 8 in the cylinder head 9 of a' cylinder f0 containing a piston I I in connection with which the indicator is tobe used. The plug-Ehas a head I2 that may be knurled as a convenient means for inserting the plug within the spark plug opening 8-. A counterboredthreaded opening t3 is formed in theplug 6; as shown in Fig; 2, to receive the threaded portion of a tubular body l4 provided with a shoulder I5 to form a stopby engagement with the bottom of the counterbored opening 13. The body extends through the plug 6, projecting out of said plug at its inner end.

The tubular body also includes an adjusting head I6 that is tubular and receives the end of the tubular body [4 the two parts being rigidly secured together in any suitable manner. end of the head I6 may be knurled as at 11 if desired to facilitate turning movement of the en-' tire body for adjusting purposes as will be hereinouter tip' end; of the supporting. body, as shownin Fig. 2. The rod projects out. or the body at this end and has a contact 28 the form of a ball secured at its end. The oppositeend or the indicator rod constitutes an indicating finger 29 that operates connectionwith the graduations in the sight: glass 22..

A- spring 30 is secured at one end to the inner surtace oi the indicator case inside of the flange r8 the oppositeend. or this spring. having a 3t through which the indicator rod 25 extends, the spring aotingto bias the indicator rod to locate the: finger piece at" the zero and of the scale:-

It will be noted that'- the rod extends in a diagonal direction through the tubular support insuch manner that in its working: position it is located at one Side of anaxial line: through the support; this being the position required for obtaining the results for which the instrument is designed. The finger 28 extends through a slot 32 formed through the botto'm of the indicator case including the sight glass and by turning the case on the adjusting head IS the contact 28 will be toward the end of the cylinder in its compres- The sion stroke air is forced through the tubular support and out of a whistle opening 34 in the nipple 24.

In the use of the device the tubular support comprising the parts I4 and I6 being at or near the outer limit of their play in the supporting plug 6, the latter having been secured in the spark plug opening 8 and the contact 28 and nipple 24 having positions as hereinbefore explained, the engine is operated by hand thereby moving the piston -ll toward the end of the cylinder in its compression stroke. This movement of the piston will force air from the chamber in the cylinder into the'hole 33 through the tubular support and out of the whistle opening 34 thereby creating a whistle noise.

nears the end of its compression stroke, the com pression having been reduced the whistle noise will cease, this denoting that the piston is near ass rts As soon as the piston- 3 on the tubular :body and engaged with the plug and that the invention may be carried out by other means and applied to uses other than those above set out.

I claim:

1. A piston positioning indicator comprising a supporting plug adapted for attachment within the spark plug opening in a cylinder, a tubular body mounted in said supporting plug, a thread connection between said tubular body and plug for-adjustably placing said tubular body in different fixed positions insaid plug relatively thereto lengthwise of said body, a lock nut threaded T for securing said tubular body in different adthe limit of its compression stroke but not having quite reached it. The tubular support is 'now turned to screw it inwardly Within the supporting plug 6 by use of the knurled end I! ,and this turning movement of the support is continued until the indicatornfinger 2}] denotes aslight movement, this indicating that the piston has touched the contact 28. .The engine is nowagain turned by hand, the movement of the indicatin finger is noted, and as. soon as such movement ceases it is known that the piston has reached the limit of its compression stroke 1 ,7

In adjusting the position of the tubular supportv as above described turningxmovement of such support shouldycease with'the nipple 24 and the contact .28 'in line on thezsame side of the :instrument as hereinbefore described, the

nipple being located to point to the axis of the crank shaft of the engine, it being assured that withv the nipple pointedin thisdirection thecon tact willbe in the position'shown in Fig. 1 pointing diagonally downward to contact. with the surface of the end of the piston. v

.A lock nutv 35 is screwthreadedly'engaged with the tubular body l4 for the purpose of 1 securing the; tubular body in any position to which it may have been adjusted, relatively to the supengine or of any one make of engine.

, Itwill be noted that the spring 30 is of hairpin shape, the ring 3| being located at the bend ofathe spring and the branches each terminating in bent ,ends secured to theinner surface of the indicator case I8 as shown in Figs, 2 and.3 of

the drawing, and that the rod is formed square to conform to the shape ofthe slot 32, as shown inFig, 2, j

In accordance with the provisions of the patent statutes I have described the principlesofoperation of my invention, together with the device which I now consider to represent the best embodiment thereof; but I desire to have it understood that the device shown is only illustrative -justable positions, an indicating rod extending for contact with the end of a piston within said cylinder, a pivotal bearing for said rod within said tubular body, and means at the outer end of the instrument for denoting movement. of the indicator rod; 1 1d f 2."A piston positionin'g'indicator comprising a supporting plug adapted for attachment within the" spark plug opening in a; cylinder and having an unobstructed bore extending completely therethrough, a tubular body mounted in'said supporting plug and extending completelythrough the ,bore therein to position its innerend within the compression chamberin said cylinder, means for adjustably placingsaid tubular body in different positions in said. plug relatively thereto lengthwise ofsaid-body, tin-indicating; rod extending within said tubular body from'the outer to the inner end thereof with its inner endprojecting for contact with the end of said piston beyond said body, a pivota1 bearing for said rod within said tubular body in proximity-of the inner end thereof andwithin the cylinder for amplifying movement of the outer end of the rod, and means at the outer'end of the instrumentfor denoting movement of said indicating rod,

3. A piston positioning indicator comprising a supporting plug adapted'for attachment within the spark plug opening in a cylinder, a tubular ,body mounted in said supporting plug, mea,ns for adjustably placing said tubular bodyiin different positionsin said plug relativelylthereto lengthwise of said bodyyan indicating rod-extending diagonally within said tubular body from one side toward the opposite side thereof and pivotally and rotatably mounted therein with opposite ends of said rod located laterally thereof on opposite sides of said pivot, a contact member on one end of said rod and an indicating finger on the other end of said rod, a cap having a cross slot in its outer end rotatably mounted onone end of said tubular body and within which said in dicating rod extends with the finger projecting through the cross slotwhereby rotation of said cap will produce a relative change in position of said finger eccentrically to the axis-of said tubular body, and 'meansupon said cap for denoting the amount of movementof said indicatin finger. 1

' FOSCOE H. 'ANDRUS. 

